Evolutionary Impact of Cytoplasmic Sex Ratio Distorters on Host Reproductive Biology

许多动物的细胞内都有细菌;有些是无害的，但另一些被称为生殖寄生虫，自私地操纵宿主的生殖系统。该项目调查了一种名为Wolbachia的广泛生殖寄生虫在多大程度上塑造了一种常见的热带蝴蝶Hypolimnas bolina的生殖生物学。在南太平洋的一些岛屿上，沃尔巴克氏体有选择地杀死雄性蝴蝶，从而杀死雄性H。在沃尔巴克氏体感染率高的岛屿上，博利纳更少见。这项研究通过比较不同性别比例的岛屿上的蝴蝶种群，来探讨沃尔巴克氏体感染是否导致了新的性特征的进化。这项工作将（i）使用遗传标记确定蝴蝶的种群历史;（ii）描述不同岛屿上蝴蝶的性特征;（iii）测试沃尔巴克氏体感染是否解释了H.博利纳。最近的证据表明，生殖寄生虫在昆虫中广泛存在，并且在自然种群中的频率极高。 考虑到感染对宿主的重要影响（杀死雄性是一个戏剧性的例子），生殖寄生虫可能在生殖系统的设计中发挥重要作用。Wolbachia-Hypolimnas案例研究为这一假设提供了有力的检验。

Many animals house bacteria that live inside their cells; some are harmless but others, termed reproductive parasites, selfishly manipulate the host's reproductive system. This project investigates the extent to which a widespread reproductive parasite named Wolbachia has shaped the reproductive biology of a common tropical butterfly Hypolimnas bolina. In some South Pacific islands, Wolbachia selectively kills male butterflies and consequently male H. bolina are rarer on islands with high levels of Wolbachia infection. The study addresses whether new sexual traits have evolved as a result of Wolbachia infection by comparing butterfly populations on islands with different sex ratios. The work will (i) determine the population history of the butterfly using genetic markers; (ii) characterize butterfly sexual characteristics on different islands; and (iii) test whether Wolbachia infection explains the evolution of sexual characters in H. bolina. Recent evidence indicates that reproductive parasites are widespread in insects and that they can reach extremely high frequencies in natural populations. Given the important impact of infection on the host (male-killing being a dramatic example), reproductive parasites could play a major role in the design of reproductive systems. The Wolbachia-Hypolimnas case study provides a powerful test for this hypothesis.